Hubble lives! See its top 10 images from 2022

Astronomy’s greatest story for 2022 was the JWST.

This remarkable three-panel image showcases the same region of space: the Pillars of Creation. On the left, the 1995 Hubble view is shown. At center, the follow-up 2014 Hubble image, with an upgraded instrument suite, is presented. At right, the 2022 view, taken with JWST’s NIRCam imager, is displayed. The variety of features showcases the power of multiwavelength astronomy, but also subtly shows the Pillars shrinking, as external radiation evaporates them away.

With spectacular infrared views, it’s unveiling our Universe like never before.

Over the course of 50 days, with a total of over 2 million seconds of total observing time (the equivalent of 23 complete days), the Hubble eXtreme Deep Field (XDF) was constructed from a portion of the prior Hubble Ultra Deep Field image. Combining light from ultraviolet through visible light and out to Hubble’s near-infrared limit, the XDF represented humanity’s deepest view of the cosmos: a record that stood until it was broken by JWST. In the red box, where no galaxies are seen by Hubble, the JWST’s JADES survey revealed the most distant galaxy to date: JADES-GS-z13-0. Extrapolating beyond what we see to what we know and expect must exist, we infer a total of ~2 sextillion stars within the observable Universe.

But in optical wavelengths, Hubble remains unsurpassed.

In measuring the expansion of the Universe, the ability to detect individual stars (and measure their distance/properties) in the same galaxies where type Ia supernovae occur is a key step in building a cosmic distance ladder. 36 such galaxies, which host both identified Cepheid variable stars and type Ia supernovae within them, are captured by Hubble, which helps astronomers compute the Hubble expansion rate of the Universe.

Launched back in 1990, Hubble’s world-class capabilities still generate cutting-edge scientific results.

This image showcases the spectra of four of the galaxies contained within the Hubble Ultra Deep Field. The spectrum teaches us about the stars inside, its star-formation history, its level of chemical enrichment, and its redshift and distance from us. Hubble’s eventual wider-field successor, the Nancy Roman telescope, will have ~200 times the field of view and will be able to take spectra for every object within it. Although these galaxies are receding away from us so quickly that they cannot be reached, even if we sent a light signal from Earth right now, they will always remain visible with advanced enough technology.

From here to its observational limits, let’s count down 2022’s top 10 Hubble images.

The quasar-galaxy hybrid GNz7q is seen here as a red dot in the center of the image, reddened because of the expansion of the Universe and its great distance from us. Although it’s been exposed in the GOODS-N field for over 13 years, it was only flagged as an object of interest in 2022, as its spectrum reveals properties of both galaxy and quasar. One of the most distant quasars ever observed, its light appears to be stretched out not only in wavelength, but in time as well.

10.) Galaxy-quasar hybrid GNz7q. This bright, dusty object showcases a cosmic transformation in action.

By observing a region of sky toward the galactic center over time, Hubble captured a large number of Milky Way stars and was able to tell how their brightness varied over time. One of those stars, highlighted in the inset panels from August of 2011 to August of 2017, brightened significantly but briefly: consistent with being caused by a microlensing event from a passing, intervening black hole. The observed microlensing rate is consistent with astronomers’ estimates that there are approximately 100 million roving black holes within our galaxy: not enough to account for the “missing baryons” required by the Universe.

9.) A microlensing black hole. Their gravitational passing temporarily brightens background stars; microlensing reveals otherwise unseeable black holes.

On September 26, 2022, NASA’s DART mission impacted asteroid Dimorphos, which is a moonlet of larger asteroid Didymos. In the aftermath of the collision, a secondary tail developed between October 2 and 8, which was an unexpected development. The Hubble observations provided the best-quality detail of the double tail.

8.) A DART-created double tail. After colliding with asteroid Dimorphos, twin dust tails were captured by Hubble.

The stars of the Peekaboo galaxy, also known as HIPASS J1131–31, can be seen by Hubble even in the glare of the nearby foreground star from our own Milky Way. The stars within the Peekaboo galaxy are exceedingly low in chemical enrichment, indicating very little star-formation within it over the Universe’s history. Perhaps remarkably, the only stars identified in the Peekaboo galaxy are a few billion years old; there is no old population of stars from the earliest stages in the Universe, a mystery that has yet to be solved.

7.) Peekaboo galaxy HIPASS J1131–31. This dwarf galaxy contains near-pristine material, visible despite a bright foreground star.

In December of 2010, Hubble imaged galaxy cluster Abell 370, which gravitationally lenses many of the astronomical objects behind it. In a distant galaxy, a supernova went off, and Hubble saw it on triple replay, with the light arriving days apart due to gravitational differences along each light-path. The supernova brightens, fades, and cools over time, and those differences are revealed by comparing the three images with one another, both initially and over time. Unresolved supernovae in distant galaxies can artificially increase the inferred brightness, normally ascribed to the stars within a galaxy.

6.) A triply-lensed supernova. Hubble saw the same event on triple replay, 8 days apart.

When major mergers of similarly-sized galaxies occur in the Universe, they form new stars out of the hydrogen and helium gas present within them. This can result in severely increased rates of star-formation, similar to what we observe inside the nearby galaxy Henize 2-10, located 30 million light years away. This galaxy will likely evolve, post-merger, into another disk galaxy if copious amounts of gas remains within it, or into an elliptical if all or nearly all of the gas is expelled by the current starburst. Starburst events like this were much more common earlier in cosmic history than they are today.

5.) Dwarf starburst galaxy Henize 2-10. Hubble reveals stars, pink clouds, dust lanes, and a supermassive black hole inside.

In 2013, a supernova went off in galaxy NGC 3287. Hubble imaged the galaxy and the location where the supernova went off many times over the subsequent years, identifying not just the fading supernova light but also a steady source of ultraviolet light: identified as the binary companion of the supernova’s progenitor.

4.) A fading supernova. Whose light, over time, reveals a bright, surviving companion star.

While there are many instances of numerous galaxies in the same region of space, they normally occur either between two galaxies only or in very dense regions of space, like at the centers of galaxy clusters. Seeing 5 galaxies interacting within a space of less than 1 million light-years is an extreme rarity, captured in gorgeous detail by Hubble here. As all of these galaxies are still forming new stars, they’re all classified as “alive” by astronomers.

3.) Hickson Compact Group 40. This five-galaxy smashup spans just ~200,000 light-years across.

The gravitationally lensed star Earendel, the Sunrise Arc that comprises the background, lensed galaxy of which Earendel is a part, and the full cluster WHL0137–08 are all shown in the inset and background images, above. The entire galaxy, called the Sunrise Arc, appears three times, and knots along its length are more mirrored star clusters. Earendel’s unique position right along the line of most extreme magnification allows it to be detected despite its relative faintness; most objects that are faint and far away remain invisible to us.

2.) Lensed star Earendel. Inside the “Sunrise Arc,” Hubble discovered Earendel: our most distant individual star.

From a visual perspective, Hubble’s view of Arp 143 makes perhaps its most striking and beautiful image of 2022. The pair contains the glittery, distorted, star-forming spiral galaxy NGC 2445 at right, along with its less flashy companion, NGC 2444 at left.

1.) Colliding galaxy pair Arp 143. These distorted, interacting galaxies create gas-rich splashes of star-formation.

This portion of the Hubble image of Arp 143 showcases the new stars (in blue) formed as a result from gas stripping, heating, and shocking in the space between the two main galaxy members. Stars have been forming throughout the Universe over the past 13.6 billion years or so, but the ones that survive today weren’t formed evenly or under the same conditions over all of cosmic history.

Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.